Machines or equipment often contain energy sources that can be potentially hazardous to workers if these energy sources are not properly controlled and maintained during servicing of the equipment. These energy sources may be, as some non-limiting examples, electrical, mechanical, hydraulic, pneumatic, chemical, or thermal in nature.
In order to protect workers from these energy sources while servicing or maintaining the machines or equipment, proper lock out/tag out procedures and practices may be voluntarily adopted or may be required by the Occupational Safety and Health Administration (OSHA). What constitutes appropriate lock out/tag out practices and procedures will largely depend on the specific equipment. Lock out/tag out procedures and practices involve following pre-determined steps or operations in order to disable the machinery or equipment to prevent the release of potentially hazardous energy before the equipment is maintained or to ensure that, when the equipment is placed back into service, workers remain protected from the potentially hazardous energy.
Some non-limiting examples of lock out/tag out devices can be found in U.S. Pat. Nos. 5,122,624; 5,300,740; 5,500,495; and 6,727,441 and U.S. Patent Application Publication No. 2004/0245077 which are incorporated by reference. U.S. Pat. No. 6,727,441 describes a switch lever lock out assembly engagable with a switch to prevent operation of the switch having a key-engagable mechanism to unlock the lock out assembly. U.S. Patent Application Publication No. 2004/0245077 describes another switch lock out assembly for locking out a switch having a pivotally-mounted movable tongue.